To me, one of the redeeming qualities of units in Racket is that they make
"the tent" bigger. Modules may usually be the right way in Racket, but the
grace of Racket is that modules are not "The one true way" because the
Racket community tends to eschew the OTW concept when it comes to computer
Stack overflow today led me to something … very strange. I feel like I must be
missing something crushingly obvious.
To reproduce: start racket at the command line or hit “run” on a definitions
window containing only “#lang racket”.
Then, paste:
(define map (lambda (l f)
(cond
((nu
Huh? Serves you right for using the top level. It works fine if you place it in
the definitions window :-)
> Welcome to DrRacket, version 6.11.0.4--2017-12-18(-/f) [3m].
> Language: racket, with debugging; memory limit: 256 MB.
> > (map '() add1)
> '()
> > (map '(1) add1)
> '(2)
> > (map '(1 2)
At 23 Jan 2018 15:57:34 -0500, "'John Clements' via Racket Users" wrote:
> despite being inside of a binding of the name map
That's the essence of the problem. Which things are in the scope of a
top-level definition?
For example, is the reference to `f` in the scope of a binding of `f`
in
(def
Permission to paste this summary on Stack Exchange?
> On Jan 23, 2018, at 1:20 PM, Matthew Flatt wrote:
>
> At 23 Jan 2018 15:57:34 -0500, "'John Clements' via Racket Users" wrote:
>> despite being inside of a binding of the name map
>
> That's the essence of the problem. Which things are in t
> On Jan 23, 2018, at 1:03 PM, Matthias Felleisen
> wrote:
>
>
> Huh? Serves you right for using the top level. It works fine if you place it
> in the definitions window :-)
Of course, and that’s what I told the poster on Stack Exchange. I was befuddled
by the existing behavior, but I exp
Sure, with whatever improvements you'd like to make.
At 23 Jan 2018 16:53:15 -0500, "John Clements" wrote:
> Permission to paste this summary on Stack Exchange?
>
>
> > On Jan 23, 2018, at 1:20 PM, Matthew Flatt wrote:
> >
> > At 23 Jan 2018 15:57:34 -0500, "'John Clements' via Racket Users" w
Many thanks.
> On Jan 23, 2018, at 1:56 PM, Matthew Flatt wrote:
>
> Sure, with whatever improvements you'd like to make.
>
> At 23 Jan 2018 16:53:15 -0500, "John Clements" wrote:
>> Permission to paste this summary on Stack Exchange?
>>
>>
>>> On Jan 23, 2018, at 1:20 PM, Matthew Flatt wr
> On Jan 22, 2018, at 7:22 PM, Matthew Flatt wrote:
>
> I think I've never considered `splicing-parameterize` because
> parameters can be mutated, but a `splicing-parameterize` form does make
> sense. I imagine that it would be implemented by creating a
> parameterization once, then pushing the
If you want `splicing-parameterize` to compose with other macros that
might implement definition forms, there's no fixed set of definition
forms.
The other splicing forms use `local-expand` to detect definition forms,
since the small set of core definition forms can be reliably detected
in expande
You want to head expand not just look at the raw words, because an expression
can expand to (define-values (x …) …). You may wish to look at how modules,
units, and classes are expanded — Matthias
> On Jan 23, 2018, at 8:15 PM, Matthew Butterick wrote:
>
>
>> On Jan 22, 2018, at 7:22 PM,
A rule of thumb you can follow to avoid tricky bugs like this: *never use
string literals as dynamic module names.* Anywhere you see a dynamic /
reflective function on modules called with a literal string, a
contradiction exists between the programmer and the dynamic function:
1. The programmer
When the thing you want to refer to at runtime is specifically a module,
using define-runtime-module-path-index or
define-runtime-module-path (also from racket/runtime-path) may be even
better choice than define-runtime-path.
-Philip
On Tue, Jan 23, 2018 at 10:03 PM, Jack Firth wrote:
> A rule
Here is an implementation of a version of splicing-parameterize that
uses local-expand, a la other forms in racket/splicing:
#lang racket
(require (for-syntax syntax/kerncase)
(for-meta 2 racket/base)
syntax/parse/define)
(begin-for-syntax
(define-synt
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